7 Answers
7

They're mostly the same. "Based out of" often suggests that the subject maintains a headquarters or home office in the given location, but spends a majority or other significant amount of time working in other locations; "based in" suggests that the subject works in the given location most of the time. But counterexamples are common, so you shouldn't make assumptions based solely on the wording.

Agreed absolutely. I think the distinction you make does or could affect some/many/most usages, but there will be plenty of cases where it doesn't. A "non-universally-observed" nuance, but a nuance nevertheless.
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FumbleFingersJul 13 '11 at 16:24

"Based in" implies the major operations of a business or entity is contained wholly or primarily in that city. "Based out of" implies that though the "home" of the business may be there, the operations of that business take place in other places as well.

"Based out of" is a common term to refer to the home base of a military unit: the 101st Airborne is "based out of" Fort Campbell, Kentucky, but they're currently getting it done in Afghanistan. We don't usually say "based in", because unfortunately, soldiers don't get to wake up in bed next to their spouses, have a nice breakfast and then commute to war.

That would seem to be in situations where American English is used. I have heard "based out of" used by Americans in speech and writing but, not by anyone else. It's not used in the UK and certainly sounds odd and weird, from my British perspective.

I find the "based out of" and "based out of" usages to be faulty, indicating a misunderstanding of the word "based." "Based in" or "based on" are terms which, I believe, make sense considering the meaning of "based." "Based out of" and "based off of" can, of course, be explained as to what the user wants them to mean, but whether the user has made a good word choice is another matter.

As I understand the language, work and/or workers can "come out of" the entity in which they are based, but they are not "based out of" there. Ideas can come from or off of a concept, in which case they are "based on" that initial concept, not "based off of" it.

I have found a response, with reference, in a similar question which supports my answer:

You can’t base anything off of anything. Something is always based on something else.